The present invention generally relates to surface inspection and review systems and methods. In particular, the present invention relates to improved system and method for detecting and analyzing anomalies on surfaces such as surfaces of silicon wafers.
Defect review systems are widely used in the semiconductor manufacturing industry to review and analyze surface defects of an article such as a silicon wafer disc, the defects previously detected by a defect scanner such as an inspection system. Such review and analysis allow for categorization of the defects and often reveal the root cause of the defects. With the knowledge of the cause of the defects, solutions can be implemented to reduce or eliminate defects of the wafer during the manufacturing process and hence improve wafer yield.
Most defect review systems are based on either electron beam imaging of the surface including the defect or optical imaging of the surface including the defect. Electron beam based defect review systems allow for very high image resolution; however, the electron beam based defect review systems require the wafer to be placed in vacuum and have problems imaging certain materials. During the review process, electron beam related damage may occur on the surface of the wafer under test. In addition, electron beam based review process is slower and thus costly compared to optical imaging systems.
Optical imaging based defect review systems allow faster review of the surface of the wafer. However, current optical imaging based defect review systems suffer from low image resolution of the defect. Because of the relatively low resolution view of the surface of the wafer, tiny defects on the surface are difficult to review or analyze.
Accordingly, there remains a need for a system that alleviates or overcomes these shortcomings.